This study aims to determine if early embryonic development, in D2 and D3 and the blastocyst, is compromised by the fine morphology of sperm nucleus. This will draw the IMSI, in which sperm will be chosen using the classification MSOME and ICSI in which sperm morphology is elected with less magnification. Both techniques are performed in oocytes of donor , being the coohorte used for both techniques picked at random. All courses will begin as a crop sequence, using the criteria of the IVF laboratory. Transfers will be made in blastocyst stage (D5 or D6), except in cases where the number of fertilized is less than 6 or fewer than 6 embryos of acceptable quality in D3, which would transfer the same D3 . With donor oocytes, the quality of these need not be compromised and to perform the same technique in all oocytes results in pure transfers with both techniques. It allows us to compare results in term of pregnancy, implantation and early abortion rate, as well as embryo quality.